[Hannah LS (OP)]

Siegfried says:

Our face is a mirror of the complex emotional signals processed by our brain, so I would imagine that facial resemblance requires not just genetic steering...

Are there any good references?

What do you think?

[Petrochemicals]

Facial symetry and conformity are very important whaen selecting a mate. Any deviation from this is seen as a sign of abnormality and sickness. Nutrition and disease in formative years  are very influential of facial features, signifying healthy stock or not. Id3ntical twins often do not look identical.

[RD]

... I would imagine that facial resemblance requires not just genetic steering ...

Genes makes your face look the way it does , (at one point like a pug) ....

https://youtu.be/wFY_KPFS3LA?t=31s

Facial expressions are controlled by your nervous system which again came about by natural selection.

[chris]

More than 75% of the genes in your genome are operational during the embryonic development of the head and face; this is why even subtle genetic changes or traits are often manifest in overt alterations to facial structure.

So genes play a huge role in head and neck development, which thus, broadly, determines adult appearance, but superimposed on this will be life experience too, including in utero. If a mother drinks alcohol excessively during pregnancy, for instance, this may be reflected in the face structure since children born to such mothers manifest foetal alcohol syndrome, a component of which includes changes to craniofacial structure.